Liquid Biopsy

A biopsy is a critical procedure for patients with cancer—providing crucial information on diagnosis, prognosis, and prediction of response or resistance to treatment. In some cancer types, like non– small-cell lung cancer, it is difficult to resect enough tissue from the biopsy for biomarker testing, due to the health of the patient or the location of the tumour.

Liquid biopsy offers an alternative sample type that can compliment or overcome the barriers associated with obtaining tumour tissue samples. It allows physicians and labs to use plasma from the patient, when obtaining tumour tissue is not available or poses a risk to the patient.

The blood draw is a non-invasive procedure for patients and a repeatable testing method for labs and physicians. Liquid biopsy has incredible potential to transform cancer patient testing and management, and is quickly becoming a compliment to the common tissue biopsy technique.

Roche is at the forefront of innovating liquid biopsy in manageing lung cancer patients. Roche has developed a test (the cobas® EGFR Mutation Test v2) that can be used on both tissue and cfDNA in plasma to identify the mutations in the epidermal growth factor receptor (EGFR) gene associated with NSCLC. As promising research into liquid biopsy continues, Roche remains committed to directly translating that research into more accurate diagnostics and improved patient care.

*SQI feature is currently not available in the USA.

When testing plasma with the cobas^® EGFR Mutation Test v2, a unique feature called the Semi-Quantitative Index (SQI)* is included in the report. This number is designed to reflect a trend in the EGFR mutation load. By sequentially testing a patient for the EGFR mutation, tracking the SQI value and identifying a trend may lead to understanding tumour progression, an option not available in other tests.

For several decades, it has been known that tumours release markers into the blood in different ways. Cell-free DNA (cfDNA), circulating tumour cells (CTCs) and exosome mRNA are all increasingly being isolated and used to detect and monitor targets associated with cancer—for diagnosis, prognosis prediction and drug resistance monitoring.

The biggest benefit of liquid biopsies lies in the potential to detect disease progression or treatment resistance long before it would trigger clinical symptoms or appear on imageing scans. In addition, certain cancers, such as melanoma and lung cancers, tend to have at least two to four genetic mutations. The tissue samples removed for biopsy may not show all mutations whereas liquid biopsies offer an improved chance of detecting these genetic changes.

While liquid biopsies may not replace tissue biopsies for the initial diagnosis, it is increasingly becoming evident that liquid biopsy has a major advantage in detecting mutations in real time thereby enabling the oncologist to manage the patients more effectively.